A radiator is arranged for an engine as a heat exchanger to cool a cylinder block and the like. The radiator is adapted such that a radiator core is arranged between an upper tank and a lower tank; the lower tank is connected to a water pump via a hose or the like to convey cooling water, which has been cooled by heat exchanging at the radiator core, to a water jacket of the engine; and the cooling water, which has been warmed by cooling the engine, is returned to the upper tank via a hose. The radiator core is improved in terms of radiation performance by arranging a large number of fine tubes between the upper tank and the lower tank in a longitudinal direction, and arranging in parallel a large number of fins orthogonally to the tubes or arranging a wavy corrugated fin between any neighboring two of the tubes. Also, for the purpose of further cooling, a cooling fan is arranged so as to face to the radiator core, and a filter is arranged between the cooling fan and the radiator core to prevent the radiator core from clogging.
The clogging of the radiator core or filter occurs with long-term use, and in particular, if work such as dismantlement of a building is performed with use of a construction machine such as a power shovel equipped with the radiator, fibriform dust such as glass fibers used as a heat insulating material is deposited on the heat exchanger, which is likely to cause overheating, so that it is necessary to clean it every time the overheating occurs. To facilitate the cleaning work, there is publicly known a technique in which a dust capture net can be taken out and in along a rail in a vertical direction (see, for example, Patent document 1). Also, a technique in which the heat exchanger (radiator) is made removable is publicly known (see, for example, Patent document 2). This technique is adapted to remove the heat exchanger by separating an upper partition wall from a lower partition wall, and then unscrewing bolts from a seat part.
However, the technique described in Patent document 1 is not preferable because if a mesh of the net is made fine enough to capture the glass fibers, the net is clogged in a short time, and therefore the cleaning work should be more frequently performed. Also, in the technique described in Patent document 2, because the upper and lower tanks are respectively connected with hoses, a range within which the heat exchanger can be moved is limited, which not only makes it difficult to place and clean the heat exchanger at a desirable position, but also twists or removes the hoses, thus creating excessive work.
On the other hand, in recent years, a gap between the cooling fan and the heat exchanger is allocated so as to be considerably small so that an engine room can compactly contain the engine, heat exchanger, hydraulic instruments, and the like to be downsized, however, this is in a state where it is almost difficult to put a hand into the gap to perform maintenance, and therefore decomposition is the only way to perform the maintenance. Also, in the case of a cabin specification, an air conditioner is allocated, and the heat exchanger such as a condenser and oil cooler is also contained in a bonnet, so that the gap between the heat exchanger and the cooling fan becomes narrower.
Patent document 1: Japanese Unexamined Patent Publication No. 1998-47061
Patent document 2: Japanese Unexamined Patent Publication No. 2001-323506